I'm bringing this over from the post on Spectra lines for Precision Aerobatics.

"Dave Edwards--- Phil is correct on the F2D rules(no material is specified for lines), I wonder if anyone has used them in an international competition?:

Line length: 15,92 +/- 0,04 m
Minimum line diameter: 0.385 mm (no minus tolerance)

Two multi-strand control lines must be used. No free ends capable of entangling an opponent's lines, and no line splices, are permitted. Open connection connectors are not allowed.

Raises the issue of accurately measuring diameters with Spectra lines - they tend to flatten with a typical mic."

018 stainless lines will hold up to the pull test(44 lb, 22kg), but the 4 strand music wire generally used will break it fairly easily in a line tangle.

Through my Ukranian spy a number of people have used Spectra lines in Europe.  They've caused some complaints because the 4 strand F2D wire can lock itself up in only a few loops at times.  Wrapped with Spectra it locks up almost instantly.  Yaroslav Melnikov tried it at one meet in the Detroit/Toronto area a couple years ago and got the same results.

Besides measuring line diameters, how come nobody has banned the common way of doing leadouts for F2D- a folded over, open loop of music wire soldered to the leadouts with a single layer wrap of very fine copper wire and soldered up with a piece of silcon tube pushed over it.  Of course they also ignore using bits of silicon tubing(each of which has two free ends) to hold the lines to the handle.  The rules specifically show that if the ends of any loops on the handle aren't buried in it they have to be wrapped with tape.  As Dave and I found out at the last contest, the bits of silicon tubing on the handle can to a very good job entangling an opponents lines.

Phil C

I suppose the interpretation is that the silicon tubing over the open loops meets the requirement "No free ends capable of entangling an opponent's lines... Open connection connectors are not allowed."

It seems also that in many cases it is "common usage" over the formal rules.  "we have been doing it that way forever so why change unless there is a problem" 

Rules could be clearer but I am not aware of any complaints or issues around this topic in any recent US or EU events.  If people start using the Spectra lines more often, we may start to get some feedback and complaints on that and rules may need updating to address this.

Regarding Paul's comment on identifying the correct plastic material, F2D rules make no material spec so we rely (rightly or wrongly) on pull test alone.  You could fly with cat gut if it would pass the pull test...

I don't fly enough f2d to lead any changes and if it were up to me, I would keep the rules as is.  I would like to see everyone shift to Spectra but not a big deal to keep everything as is.